Intelligent Way to Diff XML

Question

I'm using a program that acts like a platform which creates its instances of objects it uses and stores them in xml format in a database. This program has a way to create a "dump" of these objects into an xml collection.

I'm looking to do a diff of dumps between our production environment and our development environment, to be able to determine any deltas between them.

Since the dumps depend on the order of items in the db, a normal diff doesn't make sense. What I need is a way for the xml elements to be sorted in both dumps before the comparison, so that the diff is more intelligent and reflects the deltas more accurately.

For example:

File 1:

<?xml version="1.0" encoding="UTF-8"?>
<foo>
     <bar1>stuff1</bar1>
     <bar2>stuff2</bar2>
</foo>

File 2:

<?xml version="1.0" encoding="UTF-8"?>
<foo>
     <bar2>stuff2</bar2>
        <bar1>stuff1</bar1>
</foo>

I'm looking for a way where the diff of the above files would result in no difference, as the only differences are white space and sub order of the elements of foo.

Any ideas on how to accomplish this with large files?

The following works with small files:

Using http://prettydiff.com/ I can accomplish this by making sure the option of "Sort markup pieces" was selected. After which I was able to diff the above and it showed things as a match.

I need to do something like this locally that will work for files that can be considerable in size.

Answer 1

Giving this some thought, I figured if there was a way to sort the xml files from command line, then I could just do a diff against the files.

My follow up googles to my thought lead me to the following: https://superuser.com/questions/79920/how-can-i-diff-two-xml-files

In the above, the key was the canonical xml sort. Since I'm using a mac, the above gave me the following for my problem, which worked me:

$ xmllint --c14n File1.xml > 1.xml
$ xmllint --c14n File2.xml > 2.xml
$ diff 1.xml 2.xml

The above should also work for you if you are on linux, or are using something like cygwin installed/setup with windows.